How Do EVs and CNGVs Compare? Really?
Mark D Larsen

February 25, 2013

2012 Nissan Leaf vs. Honda Civic CNG

For many years in my state of Utah, our legislators have inexplicably awarded a paltry $605 tax incentive for the purchase of an electric vehicle, yet a whopping $2,500 for a natural gas car. The legislature is now in session again, and I have contacted all the members of the House Revenue and Taxation Committee to object to this discrepancy. I have even compiled and provided cold, hard facts from the EPA’s website to encourage them to at least make those incentives comparable. So far... my efforts have proven futile. The latest draft of HB0096 currently under review in the committee retains those same inequitable amounts.

Let me make myself clear: I readily concede that natural gas is a cleaner fuel than gasoline, no question. However, it is a scientifically proven fact that EVs are the cleanest vehicles of all. The only explanation that one committee member has offered is the old, worn out petrolganda cliché about EVs having coal-fired “Long Tailpipes” upstream. Apparently the representatives have not read my report on both tailpipe and upstream emissions for EV and CNG drivetrains. Otherwise, they would now know that CNG does not magically appear at the filling station: those very same coal-fired “long tailpipes” are also used to drill, refine, extract, compress, transport, and pump natural gas.

I have thus compiled and posted this second attempt to educate them on the facts. Below is a list of comparisons similar to those I have drawn between the Nissan Leaf and Nissan Versa. I will send the House Committee the link, and if they still refuse to award EVs an equivalent or higher incentive than CNG vehicles, I will simply have to conclude that the do not care about cleaning up the air in Utah as much as cronyism for the natural gas industry.

Advantage: Leaf

Pollution Emissions

The EPA provides “smog scores” according to the various regulations and pollution tests mandated in each state. The score “represents the amount of health-damaging and smog-forming airborne pollutants the vehicle emits, ” i.e. what gave Utah the shameful distinction of having the worst air quality in the nation last month.


2012 Leaf

2012 Honda CNG
1 (worst) to 10 (best)

These scores are specifically for Utah. Readers in other areas can find the scores for their own states on the Fuel Economy webpage. I am confident, however, that the differences will be negligible.

Green House Gas Emissions

The EPA gives the GHG emissions in grams-per-mile; I have rendered them below in pounds per 100 miles of driving.

Lbs. of GHG
per 100 Miles

2012 Leaf

2012 Honda CNG
Tailpipe: 0 50
Upstream: 33 26
Total: 33 76

The tailpipe and upstream GHG for the Honda CNG are on the Fuel Economy webpage. EVs have no tailpipe emissions, and their upstream amounts will differ according to the electric utility in a given region. I have used a Salt Lake City zip code to extract the number for a Leaf in Utah. Readers can enter their own zip codes and see the results on the Beyond Tailpipe Emissions webpage.

The EPA clarifies that the tailpipe and upstream emissions “include CO2, methane, and nitrous oxide emitted from all steps in the use of a fuel, from production and refining to distribution and final use.” The amounts are “estimated using GREET Model 1.8 (U.S. Department of Energy, Argonne National Laboratory).” “This measure shows a vehicle's impact on climate change in terms of the amount of greenhouse gases, mostly carbon dioxide (CO2), it emits. Your choice of vehicle has the biggest impact on your overall contribution to climate change.”

It is worth pointing out that in Colorado, with twice as many coal-fired electric plants as in Utah, the EPA rates the GHG for a Leaf at 72 lbs. per 100 miles, i.e., the highest in the nation for an EV, yet still slightly less than for a Honda CNG vehicle. For this reason, the legislators of our next door neighbors to the east wisely award them a $6,000 tax incentive for purchasing an EV —ten times what our lawmakers allow!

Finally, readers also need to remember that the electrical grid will only become even cleaner in the future, as we transition from coal to more wind, solar, geothermal, and hydro. In fact, right now consumers can sign up for Rocky Mountain Power’s Blue Sky Renewable Energy program to receive their electricity from 100% clean, pollution-free sources. They could also install solar panels on their homes, an investment that would eventually pay for itself with the fuel savings from driving an EV. Conversely, they can’t generate either natural gas or gasoline on their roofs.

Fuel Economy

The EPA calculates that the amount of energy in 1 gallon of gasoline is equal to 33.7 kWh of electricity, and then applies that formula to determine the miles-per-gallon equivalent (MPGe) of an EV.

2012 Leaf

2012 Honda CNG
City: 106 27
Combined: 99 31
Highway: 92 38

As you can see, the results clearly show that EVs are much more efficient than a CNG counterpart. Of course, as everyone knows, your-mileage-may-vary. I can report that, so far, my MPGe is an extreme exception to the rule. At the end of last month, I had put 6,987 miles on my Leaf’s odometer using 1,295 kWh, i.e., 5.4 miles-per-kWh. I have therefore been averaging... 182 miles-per gallon equivalent!

Fuel Costs

Using the MPGe ratings above, the EPA calculates that it costs $1.02 to drive a Leaf 25 miles, and $1.71 for a Honda CNG. I have quadrupled those amounts to determine the cost per 100 miles.

Fuel Cost
2012 Leaf

2012 Honda CNG
per 100 Miles $4.08 $6.84

The EPA used the current national averages of 12¢ per kWh and $2.13 per gallon in these calculations. Obviously, said fuel costs will vary widely according to region.

For example, in Utah we pay approximately 8.57¢ per kWh, so it would cost only $2.91 to drive a Leaf 100 miles in this state. (In my case, however, it actually costs zero, zip, zilch —thanks to my solar panels.) As for CNG, the very lowest price currently available in the state is $1.48 per gallon, which totals $4.77 per 100 miles.

The bottom line —literally— is that, in Utah, even the cheapest CNG is 64% more expensive than electricity.

Maintenance Costs

Unlike cars with engines, EVs require very little maintenance, also lowering their operating cost over time. Here is a side-by-side comparison from Motor Trend of the estimated cost for the scheduled services during the first 5 years of ownership for the Leaf and the Honda CNG.

2012 Leaf

2012 Honda CNG
5-Years of
$1,349 $1,981

Obviously, with no oil, no fuel injectors, no sparks plugs, no air filter, no fuel filter, no automatic transmission, no belts, no muffler, etc., EVs are much easier and cheaper to maintain. Although natural gas is cleaner than gasoline, and thus does not cause as much wear-and-tear on its internal-combustion engine, maintenance costs for the Honda CNG will still be higher as the years go by.

Safety Ratings

The National Highway Traffic Safety Administration mandates that all cars sold in the U.S. must undergo a series of crash tests to determine how well their structural integrity and air bag systems will protect their occupants. The results are then assigned a number of “stars,” from 1 (the least safe) to 5 (the most safe). Here are the stars reported on the NHTSA’s SafeCar website for the Leaf and Honda CNG:


2012 Leaf

2012 Honda CNG
Frontal Crash:
Side Crash:

The Leaf has the highest, five-star rating overall --two stars higher than the Honda CNG. (Note: the latter’s crash results are from the identical 2011 model year.) I am no engineer, by any stretch of the calculator, but I suspect that the battery pack underneath the Leaf helps make the Leaf’s frame even stiffer —and thus safer.

Roominess and Comfort

As their photos suggest, the Leaf is a hatchback, and the Honda CNG a sedan, so we would not expect their dimensions to be identical, even though they both have four doors and can accomodate 5 occupants. Their interior specifications are particularly different.


2012 Leaf

2012 Honda CNG
Front Head Room: 41.2 in. 39.9 in.
Front Leg Room: 42.1 in. 42 in.
Front Hip Room: 51.5 in. 50.5 in.
Front Shoulder Room: 54.4 in. 56.6 in.
Rear Head Room: 37.3 in. 37.1 in.
Rear Leg Room: 31.1 in. 36.2 in.
Rear Hip Room: 50.0 in. 51.4 in.
Rear Shoulder Room: 52.5 in. 53.3 in.
Interior Volume: 112.8 ft.3 100.7 ft.3
Cargo Capacity: 14.5 ft.3 6.1 ft.3

The Leaf has more room for front-seat occupants, but not for rear-seat passengers, undoubtedly because the battery pack is located underneath the floor and rear bench. Nonetheless, its overall interior and cargo dimensions are much greater. Most consumers are surprised at how roomy and comfortable the Leaf is on the inside, more like a mid-size car than a compact.


Those who mistakenly assume that EVs are mere “golf carts” have obviously never driven one, let alone put pedal to the metal. Although the stats differ among the various auto websites, here is what Zero to 60 Times reports:

0 to 60 mph
2012 Leaf

2012 Honda CNG
Seconds: 7.9 10.7

Even if that site’s figures are inaccurate, what nobody will deny is that the instantaneous torque of an electric motor is a thrill to experience. The acceleration off the line is exhilarating, and the gearless surge of power allows drivers to smoothly and effortlessly merge with traffic at on ramps, and pass slower vehicles in short order.


Practically every building throughout the country has electrical outlets, and the vast majority of them are capable of providing 240V for EVSEs with standard wiring and breakers. In short, the infrastructure for EVs already exists.

Conversely, although the number of CNG stations available to the public is growing, they are still relatively few and far between. Moreover, building and supplying them will not come cheap, by any stretch of the calculator.

Advantage: Honda CNG

Top Speed

If you really want to push these cars —and your luck— to the absolute limit, the Honda CNG has a higher top speed.

Top Speed
2012 Leaf

2012 Honda CNG
Maximum MPH 93 113

I have to question if this difference is noteworthy. In either case, hauling down the highway as fast as these vehicles can go is a recipe for a big, fat ticket —and a dangerous risk, not only to the driver but to everyone else on the road. In my mind, the only situation that warrants such a high speed would be to pass a slow-moving vehicle as quickly as possible, thus reducing the chance of a head-on collision with oncoming traffic. Surely this is easily accomplished at 93 mph!

Purchase Price

The 2012 Leaf is more expensive than the Honda CNG, no question about it. However, the current $7,500 federal tax incentive lowers the price of an EV significantly, while the $4,000 incentive for CNG expired in 2010.

(minus federal
tax incentive)

2012 Leaf

2012 Honda CNG
Similar Models $37,250
- $7,500 incentive



As occurs with any nascent, cutting-edge technology, prices always start out high until production can ramp up sufficiently over time to spread the manufacturing costs across a truly mass market. Consider, for example, the earliest prices consumers had to pay for laptop computers, cell phones, DVD players, flat-screen TVs, or iPods. This is precisely why the federal government is offering tax incentives for EVs: to “jump start” a promising new industry for the good of our national security, environment, energy, and climate. After all, taxpayers have involuntarily been forced to subsidize the oil industry for years; it is high time they received at least some of that money back to purchase cleaner, alternative modes of transportation.

The good news is that the prices are already starting to fall. Now that Nissan has sold over 50,000 Leafs worldwide, and launched the new battery factory and assembly line in Smyrna, TN, the MSRP of the base 2013 Leaf S has dropped to $28,800 —only $1,000 more than the Honda CNG. With the federal tax incentive, that translates to an even lower $21,300 pricetag. As mentioned above, states like Colorado offer their residents an additional $6,000 incentive, lowering the price even further to $15,300 —over $12,000 less than the 2012 Honda CNG above! Moreover, given the significant savings in fuel costs with an EV, consumers will save even more over the lifetime of the car.

And even if one were to choose an EV that costs more than a CNG vehicle, it ultimately boils down to a matter of principle. Is it worth the higher price to help clean up the planet, transition to renewable, domestic sources of energy, and build a better world for future generations? As the old adage says: you get what you pay for.


On the Fuel Economy webpage, the EPA estimates how far these vehicles could travel before needing to refuel.

Miles of

2012 Leaf

2012 Honda CNG
100% Full: 73 248

There is no doubt that the Honda CNG can travel much farther before it needs refueling than the Leaf, although Green Car Reports states that the results from their tests are much lower than the EPA claims: “perhaps only 150 miles.” Regardless, the limited range of EVs is probably the most worrisome stumbling block for consumers who consider buying one. The irony, however, is that the Leaf’s range is actually twice as far as the vast majority of us drive on a daily basis. It is a simple question of math: since the NHTSA reports that the average driver puts 13,475 miles per year on the odometer, that amounts to only 37 miles per day. Few of us realize that such is the case, and erroneously assume that we “need” more.

Of course, once in a blue moon we do drive farther than that. For example, I visit family out-of-state two or three times per year. Like most households in this country, however, I have two vehicles, and keep a “backup” gas car on the other side of the garage for those rare long distance journeys. Even with only one car in the home, if such trips are as infrequent as mine, one could easily afford to rent a gas or hybrid vehicle on those rare occasions, thanks to the fuel savings with an EV.

The crucial question is: how many miles do you drive daily? Tally the miles that you’ve put on your odometer during the past year, then divide by 365. You could also use Nissan’s range calculator map to gauge how many miles you actually drive on a typical workday or weekend. Most consumers are actually surprised to discover that an EV would more than meet their driving needs on a daily basis. The trick is to use the right tool for the right job. To hang a picture on the wall, we do not need to use a sludge hammer.

And again remember: your-mileage-may-vary. In my case, as I mentioned above, so far I have averaged 5.4 miles-per-kWh in my Leaf, rather than the EPA’s estimated 2.94. At that rate of consumption, in theory I could drive more than 100 miles per charge. In practice, however, I have driven an average of only 23 miles per day since taking delivery —not even 1/3rd of the EPA’s range prediction above.


Another difference that disturbs most consumers is that it typically takes much longer to recharge an EV’s batteries than to fill an ICE’s tank. Of course, just how long it might take depends upon the type of charger used.

Time Needed
to Refuel

2012 Leaf

2012 Honda CNG
From Empty 26 minutes to 80%
(QuickCharge 480V DC)

7 hours to 100%
(dedicated 240V EVSE)

20 hours to 100%
(common 120V outlet)

about 20 minutes
at the pump?

Because they are so accustomed to driving ICEs, most consumers do not understand that the amount of time to refuel is not as crucial as when to refuel. Having to deviate from one’s intended route to locate and stop at a CNG filling station is hardly “convenient.” Why is it that the “low fuel” light invariably comes on when one is already running late and in a hurry? And filling a pressurized tank with CNG is more cumbersome and complicated than pumping gasoline: a 10-minute stop could easily turn into a half-hour delay.

It would be an error to assume by default that such would also be the case for an EV, with an even longer wait for the battery to charge. That’s just not the way it works. In truth, refueling an EV is more like using a cell phone than a fossil fuel car. When you get home at the end of the day, you simply plug it in to its dedicted 240V EVSE. During the night —while you’re asleep, the demand on the grid is minimal, and the rates the lowest— the charger’s timer kicks in. Perhaps the best way to think about the difference is this: an EV has a “tank” only 1/3rd the size of what you’re used to in a typical car, but... every morning that “tank” is full again. Voilà! No muss. No fuss.

This is why expanding a public charging infrastructure is not as paramount to the success of EVs as one might assume. As Nissan has learned from the CarWings data gathered to date, over 90% of charging is done at home in just this way. Those nighttime charges more than suffice for the vast majority of Leaf owners to drive an average 37 miles per day. Moreover, replacing that amount of charge in the battery only takes about 2 hours at most with a dedicated EVSE —not the full 7 hours needed to charge a completely empty pack to 100%. For example, last night it took 88 minutes for my Leaf’s 3.3 kW charger to restore the 26.6 miles that I drove yesterday. And the 6.6 kW charger in the new 2013 model is supposed to be nearly twice as fast. An empty-to-full charge is rarely —if ever— needed.

In summary, Utah legislators need to take a close look at the actual figures above. If the state is going to encourage cleaner transportation to improve our air quality once and for all, they need to award a tax incentive to electric vehicles that is equal to —if not higher than— that given to CNG vehicles.